Field of the Invention
The present invention relates to an impact flowmeter for powders and granules, and more particularly to a space where this impact flowmeter for powders and granules is installed.
Description of the Prior Art
While impact flowmeters for powders and granules of various structures are commercially available today, there has been demand for maintaining a small installation space of an impact flowmeter for powders and granules.
As disclosed in FIG. 3, in a prior art of an impact flowmeters for powders and granules with a flow straightener which include a single detection plate provided at an angle (“Installation of automatical control of powder and granular materials by impactline flow meter,” Journal of the Research Association of Powder Technology, Vol. 7, No. 6, 1970; and “Selections of Flow Meter for Powders Including Slurry”, Measurement Technology, January 2015), a powder being an object to be measured is fed from a feeder 6 installed on top of the impact flowmeter for powders and granules, and the flow of the powder is straightened in a flow straightener 1 before the powder free-falls to a nearly predetermined position in a detection plate 2 which is provided at an angle on a detection shaft 10 of a transmitter 4 of the impact flowmeter for powders and granules. In this prior art, an increase in the space required for installation is unavoidable due to the flow straightener 1 required, as is an increase in the length in the vertical direction due to the one-plate structure of the detection plate, so that the installation space 9 inevitably measures 100 centimeters or more. Another drawback is that the weight of the detection plate 2 is limited due to the limited strength of the detection shaft 10.
As disclosed in FIG. 4, in another prior art of an impact flowmeter for powders and granules with a flow straightener which includes a single vertical detection plate (see picture 2 on page 15 of Measurement Technology, January 2015, “Selections of Flow Meter for Powders Including Slurry”), one detection plate 2 is vertically installed by being suspended inside a flow channel 3 by two leaf springs 8, and the flow straightener 1 is provided at an angle to save space. One drawback is that an installation space 9 of 100 centimeters or more is required. Another is that the impinging position, at which the powders and granules falling through the flow straightener 1 impinge on the detection plate 2, lowers as the flow rate of the powders and granules decreases, due to the friction force acting against the flow of the powders and granules. When the flow rate decreases below the critical flow rate, the powders and granules do not impinge on the detection plate 2.